Background: As cardiac surgery patients continue to age and present with more complex health conditions, the occurrence of a challenging postoperative complication known as "delirium" is becoming increasingly common. Postoperative delirium (PoD) is a complex neuropsychological disorder characterized by symptoms such as inattention, drowsiness, and agitation, which has many long-term negative health impacts. A patient-associated risk factor of PoD is presumed to be a preoperative alcohol use disorder (AUD).
Objective: The primary purpose was to determine whether preoperative alcohol use, measured using the Alcohol Use Disorders Identification Test - Concise (AUDIT-C), is predictive of incident PoD in cardiac surgical patients. The secondary objective was to determine the risk factors associated with PoD available in the Manitoba Access Cardiac Surgery (MACS) database. Hypothesis: Primary: Higher AUDIT-C scores are associated with the incidence of PoD in adults who underwent cardiac surgery. Secondary: risk factors identified from the MACS database are correlated with PoD in adults who underwent cardiac surgery. Methods: This was a single-centre, retrospective observational cohort study. AUDIT-C score and PoD (as diagnosed using the Confusion Assessment Method (CAM) – ICU in the intensive care unit or CAM on the postoperative ward) were collected for all elective patients undergoing cardiac surgery between March 2015 – September 2020. Results: The overall incidence of delirium in this study was 14.2%. There was an association between preoperative alcohol use measured by AUDIT-C and PoD (0.559 OR, 0.515-0.607 95% CI, p = < 0.001) before controlling for covariates. After controlling for age, procedure category, MoCA score, CFS, LVEF category, renal insufficiency, previous CVA/TIA, recreational drug use and CPB time, there was no significant association between alcohol use and PoD (0.376 OR, 0.070-2.011 95% CI, p = 0.253). Previously known risk factors, including age, frailty, MoCA scores, renal insufficiency, previous CVA/TIA and CPB time, were found to be significant.
Conclusion: Preoperative alcohol use measured by AUDIT-C is not a reliable predictor of PoD in cardiac surgery patients. Future research should explore the role of comprehensive measures of alcohol use on PoD.